Re: [PATCH v11 25/25] x86/cet/shstk: Add arch_prctl functions for shadow stack

[Andy Lutomirski]

On Mon, Aug 24, 2020 at 5:30 PM Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx> wrote:

> arch_prctl(ARCH_X86_CET_MMAP_SHSTK, u64 *args)
>     Allocate a new shadow stack.
>
>     The parameter 'args' is a pointer to a user buffer.
>
>     *args = desired size
>     *(args + 1) = MAP_32BIT or MAP_POPULATE
>
>     On returning, *args is the allocated shadow stack address.

This is hideous.  Would this be better as a new syscall?

--Andy